CaliciX™ 15 mg | Feline calicivirus (FCV) antiviral capsules

Active ingredient

EIDD-1931 (β-D-N4-hydroxycytidine) 15 mg per capsule Pharmacologically equivalent to more than 60 mg of molnupiravir (EIDD-2801)

Indication

Management of severe oral inflammatory disease associated with chronic or high-viral-load feline calicivirus.

• Feline chronic gingivostomatitis (FCGS), particularly where calicivirus involvement is confirmed or strongly suspected

• Juvenile-onset gingivitis and stomatitis

• Caudal stomatitis

• Ulcerative stomatitis

• Viral glossitis and lingual ulceration

• Multifocal buccal, labial and palatal ulcers

Clinical signs addressed

Oral pain and reluctance to eat, drooling, halitosis, difficulty swallowing, mucosal ulceration, gingival bleeding, and weight loss driven by oral pain.

Mechanism of action

EIDD-1931 is the intracellular active metabolite of molnupiravir. After absorption it is phosphorylated to the triphosphate form and incorporated into viral RNA by the RNA-dependent RNA polymerase (RdRp). This drives lethal mutagenesis, rapidly reducing viral replication and lowering viral load in mucosal tissue.

Compared with EIDD-2801 (molnupiravir):

• Higher antiviral activity

• More predictable pharmacokinetics

• No enzymatic conversion from a prodrug required

Reference data show EIDD-1931 to be up to 5.6 times more potent than molnupiravir. Source: https://pmc.ncbi.nlm.nih.gov/articles/PMC9227765/

Pharmacokinetics

• High oral bioavailability in cats

• Rapid intracellular activation

• Good distribution into oral mucosa, gingival tissue and saliva

• Stable therapeutic concentrations on twice-daily dosing

• High potency means a lower dose per kilogram

Safety

Contraindications:

• Pregnant queens and cats intended for breeding (theoretical teratogenic risk)

• Severe hepatic impairment

• Caution in cats with reduced renal function, particularly alongside NSAIDs

Monitoring:

• CBC every 2 to 4 weeks where treatment exceeds 6 weeks

• ALT/AST where concurrent medication is in use

• Weight and pain scoring

Adverse effects are usually mild and dose-dependent (gastrointestinal upset, transient lethargy).

Regulatory status

This product is not licensed for use in cats. It is intended for off-label veterinary use under professional supervision and requires informed owner consent.

Expected clinical course

• Drooling and oral pain improve: 3 to 7 days

• Ulcers reduce: 1 to 2 weeks

• Appetite and weight recover: 2 to 3 weeks

• Mucosal healing and reduced inflammation: 4 to 12 weeks

Choosing between CaliciX™ and CaliciX™ Max

Mild to moderate cases use CaliciX™: early ulceration, juvenile gingivitis, mild viral oral disease, gingivostomatitis with difficulty eating and drooling, moderate ulceration.

Severe cases use CaliciX™ Max: feline chronic gingivostomatitis, caudal stomatitis, extensive ulceration, marked pain, complete food refusal.

Dosage

• Under 2.5 kg: 1 capsule every 12 hours

• 2.5 to 5 kg: 2 capsules every 12 hours

• Over 5 kg: 3 capsules every 12 hours

Size 3 capsules, small and easy to give whole or with the contents mixed into food.

If the cat vomits within 30 minutes of dosing, repeat the same dose.

Duration

• Mild: 4 to 6 weeks

• Moderate: 6 to 8 weeks

• Severe feline chronic gingivostomatitis: 8 to 12 weeks or longer

Beyond 12 weeks, continue with CBC monitoring.

Signs the dose is insufficient

• Persistent drooling

• Pain on chewing

• Slow ulcer resolution

• Continued weight loss

Any increase stays within the recommended range and under veterinary direction.

Storage

Store in a cool, dry place away from direct sunlight.

Packaging

60 capsules in a vacuum-sealed pouch.

Shelf life

12 months from the manufacturing date shown on the pack.

Around 20 to 30% of cats relapse even after a successful first course.

Why relapses happen

• Calicivirus can persist in tissue after viral load is suppressed

• Stress, concurrent illness and immune changes trigger reactivation

• Some cats are simply predisposed to chronic disease

Maintenance approaches

A. Low-dose continuation. After 12 to 16 weeks at the standard dose, halve the dose and continue. Suited to cats that relapse repeatedly.

B. Intermittent dosing. Stop at 12 to 16 weeks and observe. Resume for 4 to 6 weeks at the first signs of relapse. Some cats stabilise on 2 to 3 courses per year.

C. Preventive dosing around stress. For cats whose relapses follow identifiable triggers such as a move, boarding or a new cat in the household, CaliciX™ Max can be used preventively over that period.

Early signs of relapse

• Drooling returns, even mildly

• Appetite drops slightly

• Occasional pawing at the mouth

• Bad breath returns

• Gums redden again

Acting at this stage is far more manageable than waiting for the case to become severe.

To uphold the highest standards of pharmaceutical safety, quality, and product integrity, we are unable to accept returns or issue refunds once an order has been delivered. This ensures that every product that reaches our customers has been handled, stored, and managed according to strict quality control requirements.

If your order is damaged, defective, or lost in transit, we will provide a free replacement at no additional cost to you. Simply contact our support team with your order details, and we will resolve the issue promptly.

This policy protects the safety of all customers and ensures that every product dispensed remains uncompromised and fully compliant with pharmaceutical standards.

EIDD-1931 (active ingredient, antiviral) 15 mg Dibasic calcium phosphate (excipient)